| 摘要 |
1,205,269. Tubular heat-exchangers. E. I. DU PONT DE NEMOURS & CO. 31 Oct., 1967 [7 Nov., 1966], No. 49465/67. Heading F4S. [Also in Division F2] In a heat-exchanger the tubes T are heatsealed in the tube plates 12, both the tubes and plates being of plastics materials such as a copolymer of tetrafluoroethylene and hexafluoropropylene, or polymers of amides, acetate, esters, olefins, vinyl halides or styrenes.
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